Identification, Resistance Detection Of Transgenic Wheatgrasses And Screening Of Raw Materials

Transgenic wheatgrasses were used as material. by molecular identification and resistance determination in this study, exogenous genes integration and expression in transgenic wheatgrasses were confirmed, which provided theoretical basis for the later study of transgenic wheatgrasses; at the same time, transgenic wheatgrasses with strong resistance were identified by detecting their drought and saline tolerance, and new varieties of transgenic wheatgrasses with drought and salty resistance that are suitable for China's western region were obtained in a short period. In addition, 9 wheatgrasses varieties were compared with drought and salt stress treatments,and critical indicators to evaluate wheatgrasses resistance were determined. With these evaluating indexes, varieties of wheatgrasses with strong drought resistance and saline tolerance were screened out,which provided basic materials for improving desertification, salinization in the western region of China and further research on genetic transformation of wheat grasses.The preliminary findings of this study are as follows:1.Confirmed that the exogenous bar gene,CBF4 gene and p5CS gene have integrated into the genomic DNA of wheatgrasses by PCR and Southern blot analysis.For the wheatgrasses transformed by CBF4-bar genes, 29 individual plants were transformed by bar Gene with transforming frequency of 7.67%; 31 individual plants transformed by CBF4 gene with transforming frequency of 8.20%, among which 5 individual plants were transformed by both CBF4 and bar genes with transforming frequency of 1.32%. in wheatgrasses transformed by p5CS-bar gene, 26 individual plants were transformed by bar gene and 49 individual plants transformed by p5CS gene, among which 15 individual plants were transformed by both p5CS and bar genes with transforming frequency of 15.78%.Integration numbers of CBF4 Gene, bar gene and p5CS Gene transformed to wheatgrasses are 2-5, 1-3 and 1-2 respectively.Northern blot analyses showed that some of the exogenous genes in the transgenic wheatgrasses expressed at the transcriptional level.2. Under drought stress, the moisture capacity in the leaves of transgenic wheatgrasses transformed by CBF4 gene decreased slowly, compared with the leaves of non-transgenic plants; Membrane permeability and MDA content increased less; Chlorphyll content is relatively higher; Pro and soluble protein content increased greatly; SOD, POD and CAT activity is comparatively higher. In summary, drought resistance of CBF4 transgenic wheatgrasses is higher than non-transgenic wheat grasses; CBF4 gene expressed in transgenic wheat grasses.3. Under drought stress and salt stress, compared with the leaves of non-transgenic wheatgrasses, the moisture capacity in the leaves of transgenic wheatgrasses transformed by p5CS gene decreased slowly; permeability of membrane and MDA content increased less; chlorphyll content is relatively high; Pro and Soluble protein content increased greatly; SOD, POD and CAT activity is comparatively higher. In summary, drought resistance of p5CS transgenic wheatgrasses is higher than non-transgenic wheat grasses; p5CS gene expressed in transgenic wheatgrasses.4. Different wheatgrasses response diversely to drought stress and salt stress Its drought and salt tolerance shows integrated performance of variety of metabolism . Single objective indicators do not reflect their true resistance .An objective assessment of wheatgrass drought and salt tolerance should be used for a variety of indicators of a comprehensive analysis.5. Under drought stress, Wheatgrass seed germination and seedling performs differently in drought resistance.After comprehensive evaluation of wheatgrass drought resistance, the order from strong to weak is: 249>812>738>MN>82>1007>790>268>114. Materials suitable for transgenic wheatgrass with drought resistance are 249, MN and 738.6. Under salt stress, Wheatgrass seeds and seedlings performs differently in saline tolerance.After comprehensive evaluation of wheatgrass salt tolerance, the order from strong to weak is: 82>812>1007>114, 738>MN>249>790>268. Materials suitable for transgenic wheatgrass with saline tolerance are 82, 812 and 1007.